Bio lecture 1-5 (genetics, punnet squares, scientific method)

Scientific method steps

1. make observation

2. hypothesis

3. consult prior knowledge (research)

4. formulate hypothesis

5. collect & interpret data

6. consult prior knowledge

7. draw conclusions

8. peer review

9. publish

Scientific method simple

1. observe

2. hypothesis

3. experiment

4. results

Hypothesis

an explanation based on observations and assumptions that leads to a testable prediction

experiment

a scientific test, carried out under controlled conditions

Independent variable

a factor that is manipulated in an experiment to determine its effect on a dependent variable.

Dependent variable

a factor that is measured in an experiment to assess the effect of the independent variable.

Treatment group

a group of subjects in an experiment that receives the treatment or intervention being tested, allowing for comparison with a control group.

control group

receive either no treatment or standard treatment (effects already known), or a placebo

Inheritance

How traits are passed from parents to offspring through genetic transmission and alleles.

Blending inheritance

The genetic material from 2 parents blends together

leads to a loss of variation

Particulate inheritance

when parents pass on discrete heritable units

gregor mendel —> proved through observing peas

true breeding

plants that produce offspring identical to themselves when self-pollinated.

alleles

alternative versions of genes

genotype

genetic makeup

all genes in an individual

phenotype

physical characteristics

Homozygote

2 alleles that are the same

heterozygote

2 alleles are different

Trait

specific thing (red or white)

Dominant allele

fully expressed in organisms phenotype

recessive allele

has no noticeable effect on phenotype

Gamete

haploid reproductive cell: egg or sperm that is formed by meiosis

Locus (loci)

position along chromosome

segregate

separate by some factor

gene

a portion of DNA whose sequence of nucleotides codes for a protein

DNA

a molecule composed of 2 strands of nucleotides that are wound together into a double helix

Chromosome

single molecule of DNA wrapped around protein

23 pairs

23 pair is sex chromosomes

Gene

a portion of DNA whose sequence of nucleotides codes for a protein (trait)

zygote

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

Heritable trait

variant for a character that has a genetic component and can be passed from one generation to the next parent to offspring

punnet square

most likely expected outcome of a cross

multiplication rule

each square has a 25% probability ½ x ½ = ¼

addition rule

¼ aA + ¼ Aa = ½ heterozygous

monohybrid

homozygous parents (one fully dominate and fully recessive) having heterozygous children

Complete dominance

occurs when phenotypes of the heterozygote and homozygote dominant are identical

dominant will be expressed

incomplete dominance

the phenotype of F1 hybrids is somewhere between the phenotype of the 2 parental varieties

in between

e.g. wavy hair

codominance

2 alleles affect the phenotype in separate distinguishable ways

both colors are expressed

e.g cows

antigen

protein that can trigger an immune response

A, B, AB

Epistasis

2 or more genes that affect the phenotype of another gene

e.g. labs

Polygenic inheritance

multiple genes independently affect the single trait

multiple genes determine 1 trait \

just genes

e.g.

phenotypic plasticity

how an organism phenotype changes in response to an environment

genetics are there but are dependent on the environment to be expressed

multifactorial traits

depends on both genes and environment influences

e.g. skin color (tanning)

autosomes

chromosomes that are not sex chromosomes

1-22 chromosome

Sex chromosomes

female—> XX

male —> XY

pair 23rd

Hemophilia

causes uncontrolled bleeding

alleles for gene encoding blood clotting

Mutation

permanent change in DNA sequence in the nucleotide

has to be different from what was already there

e.g. att—> atg

mutant

an individual whose genome contains a mutation in a gene or genes